I'm learning some new stuff about something called dropshipping. You find a good price at Walmart, Amazon, home depot, and then check eBay and try to find a price difference that is enough for you to profit. You do not buy the item until the person buys it on eBay. Instead of shipping it to your house you ship it to the customer. The one hard part is taxes because it's two transactions instead of one. The customer buys from you and then you buy from the retail store.
Just depends on the country/state. And the us has way too many subrules for doing this without consulting a tax professional.
I'm listening to https://blog.taxjar.com/drop-shipping-sales-tax/ learning the basics.
